Motion Blur Overview
The motion blur tab controls the calculation of motion blur. These parameters are used when you render with a standard camera or VRayPhysicalCamera with motion blur enabled. Note that if you use the VRayPhysicalCamera in your scene, some of the parameters in this section are ignored.
Motion Blur
On - turns motion blur on.
Example: Motion Blur
This example demonstrates the various parameters for motion blur.
Motion blur is off
Motion blur is on
Disable for RR cameras - Setting this option on will disable camera Motion Blur for the Render Region. This is the default. If camera motion blur is enabled, the Render Region may produce unexpected results and render a different image than the interactive view. This is a known technical limitation.
Geometry samples - this determines the number of geometry segments used to approximate motion blur. Objects are assumed to move linearly between geometry samples. For fast rotating objects, you need to increase this to get correct motion blur. Note that more geometry samples increase the memory consumption, since more geometry copies are kept in memory.
Example: Geometry Samples
The following images demonstrate the Geometry samples parameter. Duration (frames) is set to 2. All other parameters are the same as for the previous images. The higher value is set for Geometry samples the more accurate is the estimated object motion. However excessive increase of this value will result in long rendering times:
Geometry samples = 2
Geometry samples = 8
The geometry samples parameter is useful when motion-blurring complex motions, for example fast-rotating objects. Here is an example with an accelerating airplane propeller:
Geometry samples = 2
Geometry samples = 3
Geometry samples = 6
Geometry samples = 10
Note that you can control the number of geometry samples on a per-object basis (from the Object properties dialog). This is useful if you need a lot of samples only for some objects in the scene (for example, the wheels of a car) while other objects (the car body) can do with fewer samples, thus saving memory and speeding rendering.
Duration - specifies the duration, in frames, during which the camera shutter is open.
Example: Duration
The following scene consists of three-frame animation of moving cone. In the first frame the cone is on the left. In the second frame it is at the box. And in the third frame the cone is on the right:
The following images show frame 1 rendered with different duration values:
Duration 0.5 (frames)
Duration 2.0 (frames)
Subdivs - determines the quality of the motion blur. Lower values are computed faster, but produce more noise in the image. Higher values smooth out the noise, but take more time to render. Note that the quality of sampling also depends on the settings of the DMC Sampler as well as on the chosen Image sampler.
Bias - this controls the bias of the motion blur effect. A value of 0.0 means that the light passes uniformly during the whole motion blur interval. Positive values mean that light is concentrated towards the end of the interval, while negative values concentrate light towards the beginning.
Interval center - specifies the middle of the motion blur interval with respect to the Softimage frame. A value of 0.5 means that the middle of the motion blur interval is halfway between the frames. A value of 0.0 means that the middle of the interval is at the exact frame position.
Example: Interval Center
This example demonstrates the effect of the interval center parameter. The scene is a moving sphere. Here are three sequential frames without motion blur:
Here is the middle frame, rendered with motion blur and three different values for the interval center; the motion blur duration is one frame.
Interval center = 0.0; the middle of the motion blur interval matches the sphere position at the second frame
Interval center = 0.5; the middle of the interval is halfway between the second and the third frame
Interval center = 1.0; the middle of the interval matches the sphere position at the third frame
Notes
- When DOF and motion blur are both enabled, they are sampled together using the higher of the two Subdivs parameters.
- IMPORTANT! V-Ray 3.0 for Softimage does not support object-level motion blur. Only the global settings for the pass or region take effect.